Process for the preparation of organomagnesium compounds



'or in a homocyclic or heterocyclic ring. '5

Unit d States Patent ice PROCESS FOR THE. PREPARATION OF ORGANO- MAGNESIUM COMPOUNDS Henri Normant, Paris, France, assignor to Societe des Usines Chimiques Rhone-Poulenc, Paris, France, a corporation of France No Drawing. Filed Mar. 19, 1958, Ser. No. 722,394 Claims priority, application France Apr. 26, 1957' '3 Claims. (Cl. 260G665) w This invention relates to the preparation of organomagnesium compounds.

Organomagnesium compounds are very frequently prepared in a medium of a simple ether, and more especially in diethyl ether. in some cases, however, such ethers" only give mediocre yields. This is the case in particular when it is desired to react. magnesium with unsaturated compounds of thefollowing types:

2,943,115; Patented. June 28, 19,60

medium selected from aliphatic monoethers, phenolic The organomagnesium compound may be precipitated more or less rapidly and more or less abundantly in the i pure secondary solvent, depending upon the nature of the (I) Ethylenic compounds characterised'by'tlie presence" 1 of the group:

in which X represents a halogen atom e.g. chlorine or bromine, the double bond being situated either in a chain (II) Acetyleniccompounds of the formula: I

-R'CEC;X II

'i'n which X represents a halogen atom etga: chlorine, or:. v

bromine and R represents an aliphatic or a cyclic group which may be substituted by a functional grouping which does not react with magnesium compounds.

It is known thatcompounds of the type of Eorinulal.

react with magnesium with very good yields when the reaction is carried out in a cyclic ether, eg. tetrahydrofuran or tetrahydropyran or their homologues. Magd t" f th om ounds of Formula-lime cslum enva was 0 e c P 'Wpoundsof types I and II above set forth.

also be prepared in these same solvents.

Further, unsaturated halogenated organic derivatives of types I and II readily react with magnesium when the reaction medium employed is a polyethylene glycol" diether.

solvent, the nature of the halogen derivative employed and the proportion of solvent introduced. However, good results are generally obtained with good agitation and appropriate heating.

. r In another method of performing the invention, when the initial reaction in the primary solvent has been completed, the reaction is continued in a mixture of the primary solvent and the secondary solvent. It is thus gen- ,erally possible to obtain completely homogeneous mixtures and to produce very good yields.

The primary solvents employed according to the present invention are cyclic ethers, such as tetrahydrofuran, tetraydropyran and their homologues, and polyethylene glycol diethersof the formula: V

.in which, R, and R represent the same or difi'erent alkyl' group s, preferably those containing from 2 to 4 carbon atoms, and n is a whole number, preferably 2 or 3.

The secondary solvents employed according to the invention are the aliphatic monoethers, including those substituted by an aromatic group, the phenolic ethers, and the formals. The following ethers have been found particularly useful as secondary solvents in the process of the invention: diethyl ether, isopropy-l ether, normal butyl ether, methyl-isopropyl ether, methyl-isoamyl ether, methyl-benzyl ether, anisole and methylal.

The halogen derivatives of unsaturated organic compounds -used in the process of the invention may be com- 7 The reaction is preferably carried out as with an ordinary Grignard reagent, that is to say, with a dry apparatus and with dry reactants, under a current of nitro- Although the variety of solvents which can thusbe used is fairly wide and in turn renders possible a wider industrial application of the organomagnesium compounds, there are applications for which the use of other solvents appears desirable. Thus; questions of solubility or of convenience of recovery maymak e it desirable'to use, depending upon circumstances, either simple ethers of the aliphatic series, such as diethyl ether, diisopropyl ether, and normal butyl ether, or aromatic ethers such as anisole, or to have recourse to solvents such as ,t-he" formals. Unfortunately, in this category of solvents, the

halogenated derivatives of types I and ll do not react withi eo magnesium, or react to a limited degree, even in the presence of iodine, and mediocre yields are consequently obtained. I

According to thepresent invention there isprovided a process for the production of organomagnesium com: pounds which comprises reacting magnesium with a halogen derivative of an unsaturated organic compound in an inert atmosphere,.where in the reaction is initiated with a small portion of thesaid halogen derivativeworking in a primary solvent medium selected from cyclic ethe'rsand reaction occurs.

gen, and may be performed in practice in the following manner. All the magnesium is covered by the primary solvent, which is chosen as a function of the subsequent operations, and there may be added an iodine crystal,

followed by a smallquantity of unsaturated halogenated compound in the formofa solution 'in a littleiof the/same Y primarysolvent. The mixture is slightly heatedfif'dsired, to start the reaction. The primary solvent is there after replaced by the preferred secondary solvent for the remainder of the. operations or, ifit is preferred to .work in a mixed solvent medium, the secondary solvent is simply mixed with the primary solvent. The addition of the halogenated derivative is then continued, the rate of the addition anld if--desired the hat in'g being so adjusted that no violent reaction and no stoppage ofthe .1 16 reac ion proceeds normally at about 30-60" 0; Wiieran the reactarit has been intropolyethylene glycol diethers, the primary solvent. medium is then "replaced by or mixed with a secondary solvent the magnesium derivativeissparingly soluble.

duced, the heating is continued at a temperature of (3;, or with reflux of the solvent-if it boils at a temperature lower than 80 C., for a period of time varying in accord ance wlth the circumstances.

, When the arran emenesium derivative formed is completely or" almost si u'ble, this additional heating may be fairly short and may amount to about 30 minutes; Agitation gene motes theperformance of the process, espefi The following examples illustrate the invention, but are not to be regarded as limiting it in any way. They illustrate the simplicity of the process and the advantages thereof in terms of the yields obtained in the subsequent condensation of the. products with derivatives capable of reacting with magnesium compounds.

Example I To 0.2 gram-atom of magnesium are added 10 cc. of anhydrous tetrahydrofuran and a trace of iodine, followed by several drops of l-bromopropene. When the reaction is established and, after decoloration, the brown colora- Carbinol Aldehyde or I yields cel- Secondary solvent employed ketone em- Carblnol obtained culated on ployed aldehyde or ketoue,

percent CH:-CH=CH iso-Crfiu-O-CH: CaHnCHO /CHOH 72 oHn CH:CH=GH CHr-CHr-O-OH CIHHOHQ OBOE 72 CH: CHa-CH=(3H CH-0-CH| CBHUCHO GHOH 70-76 Ca 7 Gem:

GH:CH=CE Di-n-butyl ether 0.31.0110 CHOH as CH:OH=CH Di-isopropylether.. 0|HuCHO CHOH 58 Colin CHz-CH=CH Methylel CfluCHO CHOH 72 GHPOH=CH M x re n wle (3 volumes CQHIICHO CHOH 12 diethyl ether (1 volume).

CsHrl Mixture of diethyl ether (1 scetone. CH:-CH=GHCOH 76 volume)/tetrahydrofuran (1 volume). 0 a

tion of the organomagnesium compound has occurred, 55 Example 11 the tetrahydrofuran is siphoned away under a current of dry nitrogen. Thereafter, 30 cc. of diethyl ether are By proceeding as in Example I with ethoxybromopropenes, the following results are obtained:

Reactent condensed Yield, Derivative of the type C=CHX with the magnesium Product obtained percent derivative H; Hz (5H CH5 introduced, and then, progressively, 0.2 gram-mol. of Example HI l-bromopropene diluted in 30 cc. of diethyl ether. The temperature is regulated from the beginning to the end of the addition of the l-bromopropene in such manner The procedure of Example I is followed using as the primary solvent medium the diethyl ether of diethylene glycol or the di-n-butyl ether of diethylene glycol and that there is no stoppage and no over-heating W n 75 s g i y 7 3 he secon ary So ve t medium, the

asserts ,y 'e nsi ind ate'dl in' the, following ta ezf, j p

By priqcepdin t s' n but; using;

' V i V v Reaetant condonsed v ,Yieldgt, Derivative otthetype O=HX with the magnesium I, 'Product obtained percent V 1 :"H derivative 5,, t.

A. PRIMARY SOLVENT: mErrEYnnrnnno-r;rimTnYnnNnenYoon :5 "1'.

cnhon emsr amenacmucnqg-cn on-om r4, cm-feikqrrnr Y em-o o-en. "one-clhcn o J ea, ransom,

m IFO-GHFGH=GHBr cmco -o'm nwo'-om-on=cH-o "a H OH: 7

nto-ofii -c onaroar-econ" imf-o orri-o=on-o 7 m '15! cm Q-Ol m0 0.11. 10

CH-CeHr-C1 oiom-on=om (oH.),cH-o.m-ornon=om '15 r'c 0 H C=CHBr H10 Cc 76 HI HI 1;. PRIMARY SOLVENT: DI-n-BUTYL ETHER or DIETHYLENE GLYOOL om-on=onar OHr-CO-CH: OH|CH=CHO so H OH:

Example IV Example V Using 1-bromo-2-n-butyl acetylene (0.2 gram-mol.) as in Example IV but employing as the primary solvent the diethyl ether of diethylene glycol and displacing this with diethyl ether as the secondary solvent, there is ob-- tained hexynyl magnesium bromide which, condensed with 0.15 gram-mol. of acetaldehyde gives methyl (l-hexynyl) carbinol in a yield of 80% calculated on the acetaldehyde.

Example VI By proceeding as in Example V but using l-bromo-Z- phenyl acetylene and condensing the phenyl ethynyl magnesium bromide with butyraldehyde, there is obtained propyl (2-phenyl-1-ethynyl)-carbinol in a yield of 75% based on the butyraldehyde.

Example VII By proceeding as in Example V but using as the pri- I mary solvent the di-n-bu-tyl ether of diethylene glycol, there is obtained methy1(1-hexynyl) -carbinol in a yield of 78% based on the acetaldehyde.

mary solvent the di-n-butyl ether of diethylene glycol, there is obtained propyl(2-phenyl-1-ethynyl)-carbinol in a yield of based on the butyraldehyde.

I claim:

1, A process for the production of organomagnesium compounds which comprises reacting magnesium with a halogen derivative of an unsaturated organic compound containing a grouping selected from the class consisting of the groupings and -CEC-X where X is a halogen atom, in an inert atmosphere, wherein the reaction is initiated with a small portion of the said halogen derivative Working in a primary solvent medium selected from the class consisting of cyclic ethers and polyethylene glycol diethers, and the reaction is continued; with the 'addition'of'the remainder of the said halogen derivative, in the presence of a secondary solvent medium selected from the class consisting of aliphatic monoethers, phenolic ethers and formals.

2. A process for the production of organomagnesium compounds which comprises reacting magnesium with a halogen derivative of an unsaturated organic compound containing a grouping selected from the class consisting of the groupings a and -CEOX where X is a halogen atom, in an inert atmosphere, wherein the-reaction is initiated with a small portion;of the:said halogen derivative working in a primary solvent medium selected from the classconsisting' of cyclic ethers and polyethylene glycol diethers, and the re;

action is continued, with the addition of the remainder halogen derivative of an unsaturated organic compound containing a grouping selected from the class consisting of the groupings s and -CECX where X is a halogen atom, in an inert atmosphere, wherein the reaction is initiated with a small Substances," Prentice Hall, 1945, pp. 29-30 and 45-4 portion of the said halogen derivative working in a pri mary -solventmedium selectedfrom the class consisting of the said halogen derivative, in the presence of a 'second-' said secondary solvent medium being added i primary solvent medium. wholly reof cyclic ethers and polyethylene glycol diethe'rs, and reaction is continued, with the addition of the remainder ary solventmedium selected from the class consisting of aliphatic monoethers, phenolic ethers and formals, the to the said References Cited in the file of this patent: 1 H I UNITED STATES PATENTS 2,054,303 Scott Sept. 15,,193 6 2,734,091 Londergan Feb. 7, 1956 2,838,508 Ramsden June 10, 1958 2,855,397 Ramsden Oct. 7, 1958 Ramsden et al -Feb. 3, 1259 OTHER REFERENCES Kharasch et al.: Grigna'rd Reactions of Nonmetallic relied on. 

1. A PROCESS FOR THE PRODUCTION OF ORGANOMAGNESIUM COMPOUNDS WHICH COMPRISES REACTING MAGNESIUM WITH A HALOGEN DERIVATIVE OF AN UNSATURATED ORGANIC COMPOUND CONTAINING A GROUPING SELECTED FROM THE CLASS CONSISTING OF THE GROUPINGS 